Field of the Invention
This invention relates to docking of an instrument head to a patient interface device during laser ophthalmic surgery, and in particular, it relates to devices, system and method that aid automatic docking based on automatic positioning using differential RF coupling between the instrument head and the patient interface device.
Description of Related Art
Significant developments in laser technology have led to its application in the field of ophthalmic surgery, and laser surgery has become the technique of choice for ophthalmic surgical applications. Ophthalmic surgery is a precision operation and requires precise coupling between the surgical tool (i.e., the laser beam) and the region to be surgically altered (i.e., a portion of the patient's eye). Movement of the eye with respect to the intended focal point of the laser beam can lead to non-optimal results and could even result in permanent damage to tissue within the eye. Given that eye movement is often the result of autonomic reflex, techniques have been developed in an attempt to stabilize the position of a patient's eye with respect to an incident laser beam.
Mechanical stabilization devices, referred to as patient interfaces (PI), have been developed for coupling the patient's eye to the laser system. A PI typically has a component that directly contacts the eye, and engages and stabilizes the eye; meanwhile, the PI is attached to the laser system, so that the laser beam can be aligned to the eye. Currently available designs of PIs typically have either a single-piece or a two-piece structure.
Using a two-piece structure, the surgeon installs a lens cone on the beam delivery head of the laser system, and installs a suction ring assembly on the patient's eye using a suction force, and then docks the two pieces (lens cone and suction ring assembly) together using the motorized gantry of the laser system. In a single-piece structure, the lens cone and the suction ring assembly are integrated as one piece. In some systems that use a single-piece PI, the surgeon first installs the PI on the patient's eye, and then brings the laser head to the vicinity of the PI using the motorized gantry, and docks the laser head with the PI. A single-piece PI, or the piece of a two-piece PI that contacts the eye, is typically a single-use item intended to be used only once.